Once I made the jump and decided I wanted to start composting, I didn’t think too far into the future. I spent a ridiculous number of hours trying to decide they type of composting (there are more than a few) and where I would put a composter. Did I want to build or buy something? The list of beginner questions seemed to go on forever.
I thought about what to put in the compost pile and how much time I was realistically willing to put into maintenance. The answer was not much. I know myself pretty well by now and I know I love ideas and projects but I get worn out quickly with chores. I didn’t need another maintenance item for my list.
What I did not put any amount of thought into was what the composter would be doing in the winter months. Now that things are cooling down where I live and we are knocking on winter’s door, im starting to have some questions.
Can I compost in the winter time? Can I continue to add things to my compost in the winter? What do I need to do to keep the compost going?
So many questions! But lets back up to the basics. What is happening in the compost pile? In basic terms, you have your “greens” or food scraps and “browns” or leaves, wood chips, paper etc. as your raw materials. With adequate time, aeration, temperature and presence of microbes, the raw materials will be processed into compost.
Suppose you have a healthy compost that you’ve started in early spring. Now you’re going into winter and what variable is going to change in the winter that would upset the process? Temperature.
What is the critical temperature range for composting?
The composting process can kick off around 90 degrees but you’re going to want a compost temperature range between 135 and 160F. You would like for your compost maintain a high enough temperature to prevent fly eggs to survive. It also can kill off any food borne pathogens that could grow in the compost. You do not want the temperature to rise above 160F.
So what produces the heat?
It’s not just the heat of the sun that is causing the heat produced in the compost pile. The heat generated in the compost is actually a biproduct of the microbes digesting the food. If the ambient temperature gets too cold, the microbes can’t generate enough heat to stay active and they go dormant. They’re hanging out until it heats up in spring again and the compost rate will pick back up as the pile can warm back up again.
So can you compost in the winter?
Well I’m going to try. Here are some tips to try to keep an active compost pile through your winter months. Keep in mind that some of us have mild winters and will have an easier time keeping an active pile while others don’t have a snowballs chance of keeping an active compost in the winter months. But if you want to try, here are some tips I’m going to use:
- Have a large compost pile. Outer layers will freeze but will insulate the inner layer
- Maximize the heat from the sun you can get in the winter. Use a black composter with a lid. If you don’t want to purchase a black plastic composter, then consider some black paint on your DIY wood composter and try to have your composter in a sunny location.
- Use a tarp over the compost to protect it from the cold wind. Remember, you’re trying to keep those little guys warm enough to keep working inside the compost. You want to protect from the wind but not cut off airflow completely.
- Don’t turn the pile. You want to keep the heat in. Turning the pile or disturbing it at all is going to cause some heat loss. Just leave it alone.
- Protect it. You can put something around it like a temporary shelter or even a small greenhouse. Keep in mind everything needs to be well ventilated and you’ll want to remove it in the spring. However, a little bit of protection from the elements and some nice sunny days may just keep the pile warm enough to remain active.
- Keep things small. You can continue to add things to your compost but avoid large things that will be more difficult to break down. If you’re putting wood into the pile, stick to small twigs or wood chips.
How much does composting slow down in the winter?
Well that depends on the temperature gradient across the pile. Composting temperatures below 90 degrees can stop the breakdown process. So if your pile is only maintaining compost temperatures in the very center, you’re only composting a fraction of what you would be composting in the summer when the temperature is more consistent throughout the pile.
Can you start a compost pile in the winter?
Depends on your temperature. It will be more difficult to start a compost pile in the winter but not impossible. Worst case scenario, it doesn’t start getting active until the spring.
We’re in the mid-west with notoriously unpredictable weather, but we usually see the extremes of all four seasons, so it should be a fun case study if I can keep an active compost through the winter! We will be keeping everyone updated through the winter to see what works for us and what was a big bust. Be sure to check back!